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How long does medical cannabis take to work?

If you have a condition that is being treated with medical cannabis in the UK, one of your most pressing questions is likely to be how long it will take to feel the beneficial effects of your treatment.

There are a number of variables that impact that answer to this question, but by far the most significant is the method by which you’re taking your cannabis medication. There are two primary ways of taking medical cannabis, which work at different speeds and last for different lengths of time:

Medical cannabis lab UK

Cannabis flower

The majority of patients in the UK use their medical cannabis in the form of ‘flower’ – i.e. the plant itself – which is then vaporised (heated to produce vapour, rather than burned by smoking, which is illegal).

This is the fastest-acting and shortest-lasting method of taking medical cannabis; the peak of the effects takes place within 10 minutes, and typically lasts for 1-3 hours (though sometimes lingering for up to 8 hours).

As a result, patients who are using medical cannabis to treat conditions like acute anxiety or panic attacks – i.e conditions that need to be treated immediately – may find that this fast-acting method of taking their prescription works best for them.

Medical cannabis oil

Cannabis oil

The other way of using medical cannabis is as an oil taken sublingually, which involves placing droplets of cannabis oil under the tongue.

Cannabis oil acts more slowly than vaporised flower, so the effects typically peak after 2 hours, but can also last much longer – sometimes up to 24 hours.

This means that cannabis oil can be more suited to treating chronic pain conditions, general anxiety or difficulty sleeping; for example, if you take a dose of cannabis oil a couple of hours before bed, you are less likely to have trouble staying asleep during the night.

Likewise, someone who feels generally anxious throughout the day will find that the effects of cannabis oil may serve to dampen their anxiety throughout the day if they take their first dose as soon as they wake up.

THC and CBD interact and bind with our own inbuilt endocannabinoid system. That system is the master controller of all neural systems in the body

How does medical cannabis affect our bodies?

Medical cannabis works by interacting with the body’s endocannabinoid system, the study of which is still in its infancy. Most studies have focused on the cannabinoids THC and CBD; THC is one of the best painkillers known to man, and CBD – also quite an effective painkiller – is known to counteract the ‘high’ effects of THC, while also inducing sleep and reducing anxiety.

“THC and CBD interact and bind with our own inbuilt endocannabinoid system. That system is the master controller of all neural systems in the body,” says Professor Mike Barnes, a pioneering medical cannabis expert. “The nervous system needs modulating – it needs switching off sometimes, for instance to stop pain or stop epilepsy. And that ‘off’ switch, that modulator that controls the nervous systems of the body is the endocannabinoid system. This explains why cannabis as a plant doesn’t have just one action – it works on pain and anxiety and epilepsy. It’s interacting with the endocannabinoid system which in turn, interacts with all bodily functions.”

What quantity and strain of cannabis is right for me?

Getting a medical cannabis prescription means you are guaranteed a high quality product and that you will know exactly what is in it in terms of the strain and the THC and CBD content. These are all variables that can be adjusted in order to ensure that the medical cannabis you are taking is perfectly suited to the condition you are using it to treat.

“One of the main benefits of medical cannabis is that you always know exactly what type you are getting, you know you are being prescribed the right type for your personal needs and you know it is a pure, high quality product,” says Dr Anup Mathew, our consultant psychiatrist. “When you are given a prescription, you know exactly what percentage of THC you are getting compared to CBD. None of this information has been available to patients who have had no option but to buy street cannabis in the past, while the illegality of buying on the street is greatly anxiety-provoking and counterproductive to the conditions it’s being used to treat.”

The same is true of selecting a particular strain for treatment – and there is a vast number of cultivated strains that we are able to choose from.

“All strains have different terpene profiles, which will give a different effect when compared to one another,” says Mamedica founder Jon Robson.

“When somebody prescribes one of these strains they’ll be looking for something that combines a certain set of characteristics that they want for treating that particular ailment. For example, Gelato is a strain which our consultants might prescribe for pain, stress, anxiety or depression. This profile is high in caryophyllene and also contains limonene and humulene which are terpenes that have anti-inflammatory, anti-bacterial, anti-depression, anti-anxiety and pain relieving properties.”

How long does cannabis stay in my system?

This depends on how frequently and for how long you have been taking medical cannabis. Very occasional use will be detectable via a urine test for up to 2 to 3 days after a dose, but more patients on a more regular and consistent dosage may find that cannabis is detectable in their system up to a month after they last used it.

Whether or not your workplace employs drug testing, we always recommend that patients inform employers of a medical cannabis prescription so that their treatment can be supported in their professional life.

“I always advise patients to inform their employer that they are being prescribed medical cannabis, so that their employers can support them at work,” says Dr Anup Mathew.

“Most patients have done so, and their employer will then contact me, usually with a list of questions about whether the treatment will impact the patient doing certain tasks and how long the treatment will last. I’ve found my patients’ employers to be extremely supportive, and they come back with feedback saying they’ve seen a marked improvement in their employees.”

Should I take my prescription at a certain time of day?

The time of day you’re taking your prescription will very much depend on the nature of your condition, the method of consumption and even what strain you’ve been prescribed.

If your medical cannabis has been prescribed to treat chronic pain, for example, you may be directed to take your first dose when you wake up so that you can spend as much of the day pain free as possible, and then perhaps before bed so that you are able to spend the night in comfort as well.

If your medical cannabis prescription is tailored towards acute anxiety or panic attacks, for example, you may be directed to take a dose of medical cannabis as and when you feel an attack is imminent or occurring.

Given that cannabis flower acts faster than oil, this will also factor into when you should take your prescription. Likewise, you may be advised to take different strains at different times of the day; the sativa strain – being more stimulating and active – might be more suited to morning and daytime use, while the indica strain – having a more sedative, relaxing effect – may be better suited to night time use.

Above all, you should take your prescription as directed by our team of expert consultants, who will assess your condition and specific circumstances before determining the best prescription for you.

From onboarding a patient to prescribing their first dosage, a huge amount of patient data is collected to ensure we get their medication right.

How should I consume my first dose of medical cannabis?

Again, the guiding principle here is to follow the prescription given by our expert consultants, which will have been tailored specifically to you and your needs in terms of size and frequency of dosage, method of administration and strain of cannabis.

That said, the approach we take with new patients is a monitored course of treatment that starts with very low doses, gradually increasing according to the individual patient’s tolerance and benefit.

“When it comes to THC-containing medicines, these are best used very cautiously, using a ‘Start Low, Go Slow’ approach,” says our consultant psychiatrist Dr David Howells. “That way, we gradually reach the ‘Minimum Effective Dose’ for symptom control, with minimal side effects. Each patient has a unique ‘Endo-Cannabinoid System’, and we’re always bearing that in mind when we prescribe treatment.”

As always, the specific needs of each patient are at the core of every treatment plan. “We have an initial consultation and we collect a lot of information,” says Jon Robson. “From onboarding a patient to prescribing their first dosage, a huge amount of patient data is collected to ensure we get their medication right. Within our eligibility / onboarding process, we take the time to understand an individual’s experience with cannabis.

“For those that are experienced, it’s important for us to learn what they are currently using from a THC and CBD ratio perspective. This enables us to then offer a regulated alternative that can provide the desired relief for their ailment. This information is then processed through our system to provide treatment suggestions based on the information collected. It’s all about tailor making the treatment to the patient”

Discover our frequently asked questions here.